Heating and cooking apparatus.



RRVBNNER.-l HEATING. AND COOKING APPARATUS.

kAPPLICATION IILED SEPT. 27, 1913A.

Patented Mar. 23, 1915.

ldd l ROBERT FRANCISy VENNER, OF LONDON, ENGLAND.

HEATING AND COOKING APPARATUS.

Specification of Letters Patent.

@tonteria Mar. 23, faille.

Application led September 27, 1913. Serial No. .Us

To all whom t may concern:

Be it known that I, ROBERT FRANCIS VEN- NER, a subject of the King of Great Britain, residing at London, England, have invented certain new .and useful Improvements in Heating and Cooking Apparatus, of which the following is a specification.

This invention relates to electric heating and cooking apparatus of the kind in which resistance conductors are employed'and has for its object to provide an improved construction and arrangement of such apparatus embodying various novel features for the purpose of improving its efiiciency and convenience in operation.

The invention contemplates, as has previously been proposed, the employment of a heat transferring lnedium which surrounds the resistance conductor and is composed of an electrically non-conducting liquid material such as oil or the like.

According to the present invention, the improved heating and cooking apparatus comprises a heating element consisting of a resistance conductor surrounded by a silbstantially horizontal sheet or layer of liquid material of relatively large area and uniform small transverse thickness, thus enabling a minimum alnount oiiliqu'id heat transferring material to be employed under conditions of maximum efficiency asregards convection by establishing the shortest possible paths between the surface of the resistance conductor and the surface to be heated.

The invention is illustrated in the accompanying drawings, Figure l of which is a view in sectional elevation illustrating the invention as embodied in a ing` vessel; Fig. 2 being same. Fig. 3 is a view in sectional elevation illustratingT a form of heating element ernbodying the invention and adapted to be immersed in liquid or semiliquid material to be heated.

Referring now to Figs. l and 2, the cooking vessel illustrated therein comprises a hollow pan of circular, oval, or other form containing a quantity of oil surrounding a resistance confluctor,.which is suitably supported and insulated from the vessel if desired. The vessel is constituted by a hollow shell eomprisingftwo parallel closely adjacent plates 1, 2 separated by a relatively thin sheet or layer of oil indicated at '3. A resistance conductor 4 is located Within the grilling or frya plan view of the ,tributed within a layer of oil between the plates l and 2 and may be arranged in any suitable form so as to insure proper distribution of heat. hollow Hanse constituted by the upturned edges 5, 6 0.,' the plates l and 2 is provided so as to inclose an annular space 7 which not only serves to provide the necessary space to permit the expansion of the oil 3, but also constitutes a wall or rim for the vessel, the material to be heated or cooked being placed upon the upper plate l in the usual manner.

Referring now to Fig. 3 and' which illustrates an immersion heating element, the resistance conductor el' is, as in the construction illustrated in Figs. 1 and 2, arranged in the interior ot a lat hollow casing or shell 8 containing a thin sheet or layer oi' oil 3 completely surrounding the resistance conductor a. The casing 8 is provided with a hollow central stem 0 by means of which the heating element may, r it required, be removed and placed in position within the liquid to be heated', the upper part of the stem 9 constituting a space for 'permitting the expansioii of the oil 3', as will be easily understood without further description.

It should be noted thatthe term i sheet or layerl as hereinabove employed is intended to convey the idea of a mass of liquid of considerable area and avrelautively small uniform transverse thickness, as the essential feature of the invention consists in the distribution ot the heat transferring medium in this manner as opposed to other distributions formerly proposed, and it will be understood that while one manner oi carrying the invention into practice has been described and illustrated in the drawing, the invention not limited thereto but includes other modifications and applications of the essential principle or' the invention above described.

llf'hat I claim is l. In electric heating or cooking apparatus. a resistance conductor laterally disrelatively thin extended and substantially horizontal layer of liquid electrically insulating material.

'2. In electric heating or cooking apparatus the combination with a substantially horizontal resistance conductor oi a layer .0f oil surrounding said conductor. said layer being of relatively large area and small substantially uniform transverse thickness.

3. In electric heating or cookine apparatus the combination with a substantially horizontal plane layer of liquid electrically insulating materiah of a resistance conductor of extended form located approximately in a horizontal plane coinciding with the middle plane ot' said layer.

4. In electric Vheating or cooking appa' terial when heated.

6. In electric heating or cooking apparatus the combination with a hollow flat horizontal casing, of a hollow annular upwardly extending projection on saidcasing constituting a rim for the upper surface thereof, a at'resistance conductor of extended form located symmetrically within the interior of said casing, .and a body of oil completely filling the interior of said casing and partly extending within said Vhollow projection.

.7. In an electric heating or cooking apparatus, the combination with a horizontal casing having a hollow upwardly extending projection, of a resistance conductor of extended form located within the interior of said casing, and a liquid body in said casing and partly extending within said hollow projection.

8. ln an electric heating or cooking apparatus, the combination with a fiat hori zontal casing having a hollow upwardly extending projection, of a flat resistance conductor of extended Jforni located within the interior oit said casing, and a liquid body in said' casing and partly extending within said hollow projection.

9. In an electric heating or cooking apparatus, the combination with a flat horizontal casing having a hollow upwardly extending projection, of a flat resistance conductor of extended form located symmetrically within the interior of Asaid casing, and

a body oiE oil in said casing, and partly extending within vsaid hollow projection.

l0. ln electric heating or cooking appa ratus, the combination of a hollow ilat hori- *Y zontal casing having a hollow upwardly extending projection constituting a rim thereoi. a flat resistance conductor oi extended il'orn'i located within said casing, and a body ot oil in said casing and partly extending within said hollow projection. i

ll. ln an electric heating or cooking apparatus, the combination of a hollow flat horizontal casing having a hollow annular upwardly extending projection constituting a rim thereof, a flat resistance conductor of extended forni located in the interior of' said casing, and a body of oil in said casingl and partly extending within said hollow projection. l

'lin witness whereof l have hereunto set my hand in presence of two subscribing witnesses.

ROBERT FRANOIS VENNER. Witnesses H. A. Corn, A. A. Bansin. 

